Because you have too little time for sex

You don’t make love as much as you used to.

You tell each other that this is only natural, after all these years.

On weekday nights, you try to get enough sleep before work in the morning.

On weekday mornings, you have to get up when the alarm goes off, else you’ll be late for work.

The rest of the time, you’re just too exhausted.

It’s only natural.